Many New England wildflower species used in planting urban pollinator landscapes require stratification for the seeds to successfully germinate. Specifically, some they require a cold, moist period mimicking the natural winter season they would typically experience. Luckily, this is easy to accomplish even without a yard! Here are three easy, and sustainable, methods of winter sowing that provide an option for every urban gardener.
Coffee filters/ paper towels and snack bags.
The first option uses common household items you may already have, paper coffee filters/ paper towels and reusable plastic baggies. Lightly wet the paper towel and spread seeds across in a thin layer. Our preferred method is to mix seeds with moist soil and wrap in a coffee filter. This keeps them moist and protects them from light. Place in plastic baggie and seal tightly. The seeds should be stored refrigerator for 4-6 weeks depending on the species. Be sure to check for mold once a week!
Glass Jars are another handy, and eco-friendly, option. Simply mix seeds with some moist seedling starter, label and put in the fridge for the required time.
Milk or water gallon-sized jugs are the perfect upcycled item for this option, but soda bottles and large clear juice bottles work just as well!
Step 1: Cut along the middle of the jug, leaving a hinge under the handle. Also make at least four drainage holes along the base of the jug. Use strong, waterproof tape to reinforce the hinge. I like to place tape on on the front, top of the jug for a fun label!
Step 2: Fill the bottom half of the jug with well-draining seed starter mix. Water well and allow to fully drain.
Step 3: Spread seeds along the top of soil and cover with a fine layer of soil. This is my second year in my current urban garden, and I am using seeds I harvested from this past season. You can also order seeds online, or post in community groups or in local garden club pages to see if anyone is doing a seed exchange.
Step 4: Tape along the cut line to secure the seeds from being knocked out or roaming pests. Don’t forget to LABEL THE JUG! Nothing is worse than a full jug of seedlings with no idea what they are.
Step 5: Place the jugs in a spot that is protected from wind, but has access to sun and rain/snowfall. Morning sunlight is especially important to allow for proper seedling growth.